It is useful to define, for introductory purposes, the notion of trajectory. A trajectory is a sequence of positions described by a moving point. A trajectory can be trivial: sequence of segments connecting navigation points, or complex: combination of curves with variable radii passing through points associated with tangents to the curve. The trajectory described by a person will depend on an objective: for example, the shortest path or the fastest travel time considering lateral or longitudinal adhesion limits, as a function of the speed. A specialist will be capable of extrapolating in real time his/her optimum trajectory as a function of a limited number of information about his/her travel environment, in combination with his/her own situation (speed, orientation . . . ). Then, he/she will be able to make immediate decisions in an autonomous manner, such as pivot, rotate, slow down and accelerate, without any system imposing them to him/her.
The required and sufficient information needed by the specialist are particular points commonly designated “chord points”. It is essential for the specialist to know, at any time and simultaneously, the position, the passage direction and the tangent direction of at least one chord point to extrapolate a complex trajectory. For optimization purposes, he/she should also know his/her own speed. The only information of the position of this point is not sufficient to allow the specialist to extrapolate a complex trajectory. For example, if the chord point is a few centimeters from a wall, it is essential that the specialist integrates to pass through this chord point parallel to the wall. The tangent information specific to the chord point is thus essential for our problem. A simple series of passage points, without this tangent information, is unusable for the construction of complex trajectories.
In the particular field of sports, the objective for the athlete consists in arriving at the end of a path in a minimum time, without exiting limits of the environment imposed to him/her (ski slope, lane in athleticism, limit of the road or velodrome in cycling, limit of the road or circuit for automobile or motorbike).
The athlete should find a balance between his/her speed and his/her capacity to maintain or modify his/her travel direction in the environment. In some sports, additional parameters come into play, such as the capacity of the material to accelerate or decelerate as a function of the speed or the curvature radius, for example.
The optimization of these parameters results in the trajectory described by the athlete in his/her travel environment.
The top athlete is the one who excels both in the technique of his/her particular sport (running, moving quickly on skis, managing a deviation in a car, optimizing braking) and the planning of his/her trajectory in the specific environment imposed to him/her for a trial.
Indeed, the intrinsic performance of the athlete resulting from his/her capacities to control the body technique specific to his/her sport is not sufficient: also, his/her capacity to “read” his/her environment in order to predefine his/her own trajectories will make the difference with the other athletes.
Thus, the best athlete will be the one who will use his/her intrinsic capacities at the maximum in the environment, without exiting its limits. This is the whole purpose of the trajectory: it results from a true expertise of the athlete. It is the combination between the capacities of the athlete and the constraints of the travel environment.
This concretely results in reference points followed by the athlete along his/her path. These points can be passage points, chord points, orientation changing points, deceleration points or acceleration points.
Ideally, these points are predetermined by the athlete and his/her concentration is focused on the reference points at a distance from his/her instantaneous situation.
The system of the invention provides the athletes with innovating media in the complex approach of controlling the trajectories.
The system according to the invention can be used both in an educational approach and in an operational situation, as an efficient information support useful for handling the trajectory.
The great particularity of the system according to the invention is that it allows an efficient use both for blind and visually impaired athletes.
Generally, it is difficult for blind or visually impaired persons to move in an unknown environment without any external assistance such as another aid person or a blind stick.
Thus, there are many touch or sound navigation systems which allow blind or visually impaired persons to move in an environment, the blind or visually impaired persons being guided in the environment via touch or sound information.
The US patent application US2011268300 describes a touch guiding system, the system comprising touch stimulators within a headgear which can provide touch stimuli at different locations around the head in order to transfer information to a person, such as a direction or azimuth, the system further comprising magnetic sensors, accelerometers and/or a GPS. However, the system can provide, through touch, only one type of information at the same time to the user, thereby limiting the amount of trajectory information sent to the user. Moreover, this system does not allow to detect objects of the environment which are not in the mapping of the environment.
The US patent application US2008120029 describes a clothing touch navigation system which transfers position information to the user through touch, the system being able to provide the user, via a belt comprising four touch actuators arranged at the four cardinal points, with direction and distance information using a GPS. However, this system cannot provide the user, through touch, with other navigation information such as information of own azimuth of passage gate or information of limit of the travel environment. In addition, this system does not allow to detect objects of the environment which are not in the mapping of the environment. Furthermore, this system having only four touch actuators, the user orientation accuracy is highly limited. Finally, this system does not allow in any case a high speed use or an optimized handling of the trajectories.
The French patent application FR2771626 describes a system allowing the blind or visually impaired persons to be oriented and guided in an unknown environment, the system comprising transmitters arranged on the path and a portable object comprising touch means to inform the user of the direction to follow according to the direction of the orientation reference, the selected destination and the information transmitted from the transmitters. However, this system cannot provide the user, through touch, with other navigation information such as information of own azimuth of passage gate or information of environment limits. Moreover, the exchange of information between the transmitters and the moving object is performed via a wireless communication, thereby imposing in the object worn by the user a wireless communication receiver. This system does not allow in any case a high speed use or an optimized handling of the trajectories.
The US patent application U.S. Pat. No. 5,470,233 A describes a system allowing a blind person to move in an urban environment. This system does not allow in any case a high speed use or an optimized handling of the trajectories.
The German patent application DE 10 2011 119864 A1 describes a navigation apparatus having a touch interface. This system does not allow in any case a high speed use or an optimized handling of the trajectories. Furthermore, it does not allow a hands-free use.